Re: [PATCH] PCI: Add PCI_EXT_CAP_ID_PL_64GT define

[Bjorn Helgaas]

On Tue, Aug 06, 2024 at 10:27:46AM +0800, 412574090@xxxxxxx wrote:
> From: weiyufeng <weiyufeng@xxxxxxxxxx>
> 
> PCIe r6.0, sec 7.7.7.1, defines a new 64.0 GT/s PCIe Extended Capability
> ID,Add the define for PCI_EXT_CAP_ID_PL_64GT for drivers that will want
> this whilst doing Gen6 accesses.
> 
> Signed-off-by: weiyufeng <weiyufeng@xxxxxxxxxx>
> ---
>  include/uapi/linux/pci_regs.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> index 94c00996e633..cc875534dae1 100644
> --- a/include/uapi/linux/pci_regs.h
> +++ b/include/uapi/linux/pci_regs.h
> @@ -741,6 +741,7 @@
>  #define PCI_EXT_CAP_ID_DLF	0x25	/* Data Link Feature */
>  #define PCI_EXT_CAP_ID_PL_16GT	0x26	/* Physical Layer 16.0 GT/s */
>  #define PCI_EXT_CAP_ID_PL_32GT  0x2A    /* Physical Layer 32.0 GT/s */
> +#define PCI_EXT_CAP_ID_PL_64GT  0x31    /* Physical Layer 64.0 GT/s */

It probably makes sense to add this (with the corrections noted by
Ilpo), but I *would* like to see where it's used.

I asked a similar question at
https://lore.kernel.org/all/20230531095713.293229-1-ben.dooks@xxxxxxxxxxxxxxx/
when we added PCI_EXT_CAP_ID_PL_32GT, but never got a specific
response.  I don't really want to end up with drivers doing their own
thing if it's something that could be done in the PCI core and shared.

>  #define PCI_EXT_CAP_ID_DOE	0x2E	/* Data Object Exchange */
>  #define PCI_EXT_CAP_ID_MAX	PCI_EXT_CAP_ID_DOE
>  
> -- 
> 2.25.1
>